Freiburg 2024 – wissenschaftliches Programm

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SYCC: Symposium Controlled Molecular Collisions

SYCC 1: Controlled Molecular Collisions

SYCC 1.4: Hauptvortrag

Mittwoch, 13. März 2024, 12:30–13:00, Paulussaal

Cold and controlled collisions using tamed molecular beams — •Sebastiaan van de Meerakker — Radboud University Nijmegen, the Netherlands

The study of molecular collisions with the highest possible detail has been an important research theme in physical chemistry for decades. Experimentally, the level of detail obtained in these studies depends on the quality of preparation of the collision partners before the collision, and on how accurately the products are analyzed afterward.

Over the last years, methods have been developed to get improved control over molecules in a molecular beam. With the Stark decelerator, a part of a molecular beam can be selected to produce bunches of molecules with a computer-controlled velocity and with longitudinal temperatures as low as a few mK [1]. The molecular packets that emerge from the decelerator have small spatial and angular spreads, and have almost perfect quantum state purity. These tamed molecular beams are excellent starting points for high-resolution crossed beam scattering experiments.

I will illustrate the possibilities this new technology offers to study molecular collisions with unprecedented precision and at low collision energies. I will discuss our most recent results on the observation of scattering resonances [1], as well as bimolecular dipole-dipole collisions at collision energies down to 0.1 K obtained by merged beam configurations [2].

[1] T. de Jongh et al., Science 368, 626 (2020) [2] G. Tang et al., Science 379, 1031 (2023)

Keywords: scattering resonances; low-energy dipole-dipole collisions; Stark decelerator; velocity map imaging; crossed beam scattering